Absolutely not a good idea at all. Even with true likes, it is still hard to convert them to buyers in my experience.
I would invest my money in Facebook Ads. Because the fans you get from this ads are interested really in your service/product. If you buy fans you may have a big amount of "likes" but they aren't interested in your product and just get paid for liking your fanpage. You can't build up traffic with buying fans.
In fact it is not good. All of them are fake likes so the users do not really like your page, your content. I also buy 2k likes but there's very few of them care may post and sharing.